/"TcaV. G>^clc oxv^e Carbonic Acid, 30,00 <19'87 oxyge> 100,00 This oxide of Zinc contains 80,13 per cent, or the ore a frac¬ tion more than 51 per cent of metallic Zinc, the other consti- 12 tuents being carbonic acid, which is dissipated during roasting, and oxygen, which is got rid of during the reduction of the ore. The second species: Electric Calamine is composed of: Which gives rather more than 53 per cent of metal, but as this ore forms only a small part of the average ore, it can hard¬ ly influence the general result. These two ores were, till lately, the only Zinc ores that were used in Europe for the preparation of brass, and the extrac¬ tion of the metallic Zinc, and it is only a few years since blende (sulphuret of Zinc,) has been used. Although the blende is easily recognised as mentioned above, it is nevertheless ATery difficult to ascertain by mere inspection whether the ores con¬ tain other ingredients than simply Zinc combined with sulphur, because the sulphuret of Zinc seems to form intimate combina¬ tions with sulphuret of iron, sulphuret of copper, sulphuret of arsenic, and sulphuret of cadmium, all of which can only be discovered by chemical means, and are not perceptible to the eye. The blende from near Powell's river after being separa¬ ted as much as practicable from heterogenous matter gave: Zinc, 61,00 Iron, 1,50 Lead, 7,50 Sulphur, 21,00 Earthy matter and loss, 0,00 These analyses have been made with carefully selected quan¬ tities of the ores and in a careful manner, but in operations on a large or manufacturing scale such extreme niceties are im¬ practicable. I have therefore made several analyses of the calamine and the electric calamine as thev occur together in Oxide of Zinc, Silica, Water and other matter, 67,00 25,00 8,00 100,00 100,00 13 the ore, separating only the impurities by washing after it was pulverised; that I might thus ascertain merely the quantity of metal the calamine and electric calamine, as they occur in the mine, contained. The results of these analyses have varied very much, some of the ores were so completely purified by these mechanical labors that they produced about 50 per cent of metallic zinc; but on an average I must put down the gener¬ al result at from 40 to 43 per cent. The ore which served for my investigations was collected from the surface only, where it had been exposed to the influence of atmospheric agencies. There may be some difference in the result when the ore is not altered by exposure, but this difference will probably be favor¬ able; but even if the results were not more favorable than those which I obtained from my analyses, they must be considered as very satisfactory if we compare them with results obtained in Europe. In Lydognia the calcined calamine produces on an average from 40 to 47 per cent, and the nett loss of metal dur¬ ing the operation is considered as 8 per cent. According to Gray, one of the Zinc works produces generally from 10 centner of ore 4 centner of Zinc. It must be remembered that I took for my analyses ore that was not roasted or calcined. So far as I know, no Zinc in its metallic state has as yet been produced from its ores in any part of the United States, nor has any of our American zinc ore been employed in the forma¬ tion of Brass, all the brass that is manufactured here, being made by combining the zinc of commerce with copper. The, necessity of taking advantage of the resources so bountifully bestowed, almost on every state, have induced the inhabitants of some of the eastern states to turn their attention to their zinc mines. I received some time ago a pamphlet having for title, "On the Zinc mines of Franklin, Sussex county, N. J., by Francis Alger of Boston." In it Mr. Alger says, "As the manufacturing of pure zinc metal has become of great impor¬ tance, from its increased consumption in the arts and manu¬ factures of our country, enterprising individuals have turned their attention to the subject; and the discovery of extensive deposits of Zinc ore has been looked for, with great interest. 14 Various mines have been called into notice, and some of them have been thought of sufficient extent for profitable explora¬ tion; but as they have proved to yield nothing but common sul- phuret of zinc, no company has ventured to engage in the busi¬ ness." It must here be observed that our great deposits, are not "Sulphuret of Zinc," it is the carbonate and siliceous oxide. Mr. A. recommends the red zinc ore, which in bulk, (as it oc¬ curs in the mine,) according to Mr. A. contains some what more than the half of oxide of zinc, which oxide of zinc has al¬ so a small proportion of manganese and iron—While the Ten¬ nessee ore is richer in zinc, and is free of the "Sulphuret." In order, therefore, that our citizens may avail themselves, of these valuable resources of our State, I will describe the most improved processes by which the ores are made available in Europe. The process by which the zinc is obtained, is said to have been introduced from China into England and was first prac¬ tised in a manufactory at Bristol in that country. The ores generally used, are the two first described, the calamine and electric calamine. The ore, after being raised from the mine, is first dressed, that is, it is broken into small fragments, and the galena, pyrites and other impurities are separated as ac¬ curately as possible by hand; it is next calcined or roasted (as it is generally called) in a reverberatory furnace. By this op¬ eration, carbonic acid and water are driven off and the vol¬ ume tf the ore becomes less and more brittle. It is perform¬ ed in houses, partly in an open fire, partly, in order to save fuel, m proper furnaces. In the first case wood or stone coal is used. In the latter the prepared ore is introduced through an opening in the vaulted roof into the furnace and spread out over ;1ie floor or laboratory as it is technically called. By this opeiM.ion the ore loses on an average £ in weight, becomes more brittle, and its former color, which is principally owing to iron or ide, becomes of a brighter red. Ah.t this operation, the ore is washed, by which the lighter earthy parts are separated from the metallic oxide; this oxide, being dried is intimately mixed with about j of its weight of 15 charcoal by grinding the ingredients together in a mill, and thus becomes ready to be smelted. DESCRIPTION OF A ROASTING FURNACE. The furnace in which the roasting is performed is called, as mentioned above, a reverberatory furnace: Plate I, fig. 1, shows a longitudinal section of such a furnace used in Upper Silesia;—fig. 2, a horizontal section: a, an aperture in the vaulted roof through which the ore is introduced; b, b, two apertures in the side walls, furnished with doors which serve to introduce a kind of iron rake or bar to stir up and turn the materials; c, the chimney; d, a fire bridge; e, the grate, which is fixed a little lower than the level of the adjoining floor of the laboratory; f, a hole through which the fuel is introduced and the fire stirred up. The floor of the laboratory is formed of clean sand mixed with a little clay, and well beaten into a smooth compact sur¬ face, and this is sometimes further coated with a mixture of charcoal, powder and clay. The roof is vaulted, and low, so as to allow but a narrow space for the passage of the flame, but the precise curve to be given it, is of little consequence, provided it is as flat as is consistent with due strength, in or¬ der to contract the space between it and the floor. The ore is every hour stirred up, and after 5 or 6 hours good roasting, it is taken out, and the furnace filled again. The Silesian fur¬ nace holds 30 centner, and the fuel used is stone coal. 100 centners of ore require somewhat more than 25 bushels (15 Prussian Schekels) stone coal for its complete roasting. After this, the roasted ore is mixed with one seventh or one eighth of its weight of the charcoal dust and cinders, which fall through the grate. But as zinc is volatile in a high heat, the reduction must be performed in close apparatus like those used for distillation by means of pots or crucibles as practised 16 by the English and invented by Watt. Or in an apparatus composed of earthen tubes arranged in a vertical position, as used in Carinthia; or in an horizontal position, as practised in Liege; or again by muffles with adopters or receivers by which also a downward distillation takes place, as in Upper Silesia, Poland, Cracow, Gallicia and Grison. The English mode of reducing the ore is, as observed above, in pots or crucibles arranged in a furnace invented by Watt. "Such furn aces are used at Bristol, Birmingham, and near Shef¬ field, the first obtain the calamine from Flintshire and Men- dipshill; the last from Alston Moor in Cumberland. DESCRIPTION OF WATT'S FURNACE. The furnaces used in the above mentioned places are either quadrangular or round; the latter the most convenient, and are constructed for 6 or 8 pots or crucibles. Fig. 3 represents such a furnace; it is composed of a dome or vaulted roof sur¬ rounded by a conical chimney constructed as follows: a, dome or vaulted roof; b, chimney, to increase the draught and to carry off the smoke; c, openings in the chimney—the same number as there are pots in the furnace; d, apertures in the vaulted roof—the same number as there are pots in the furnace. Through these holes the pots are filled and closed, and the smoke ascends from the interior. In the surrounding wall, openings are left through which the pots are introduced and removed. These openings are closed again with bricks and a mortar ol clay when the pots are in it. e, grate; f, fire door; g, hole for ashes; h*on pots or crucibles. The bottom of these pots is per¬ forated with a circular hole which is closed with a wooden plug when they are filled with the calamine and coal; the heat of the furnace chars the plug and thus prevents the matter from falling down; 17 i, the floor upon which the pots are placed; it is perforated under each pot, so that the bottom of the pots can be reached from below. In the k, aperture of the pots is a sheet iron tube, diminishing in diameter downwards, to which, when the distillation is going on, a sheet iron tube is adapted in which the zinc vapors con¬ dense and fall in drops in I, vessels filled with water; The filling of the pots is performed through an opening in the upper part, which remains open during the beginning of the operation till the flame, issuing through it, assumes a blue- ish color (this color is owing to the burning of the zinc)—the aperture is then closed with a m, plate of fire clay and luted. The iron tubes are sometimes disturbed and clogged by the condensed zinc and must therefore from time to time be cleared out by a red hot iron which melts the metal. The pots may be constructed, as is shown in fig. (which I consider an improvement.) This fig. is a vertical section of it; and fig. a cast iron pipe fitted to the bottom of the crucible or pot. The chemical action in these pots during the opera¬ tion is easily understood; the heat decomposes the materials, and zinc and carbonic acid, the result of the decomposition be¬ come aeriform, which rising, have to pass through the iron tube, where they are cooled; the zinc condenses into drops of melted zinc, and the carbonic acid is dissipated through the air Several improvements in this apparatus have been intro¬ duced in England, one of which is that of Mr. Dillger, which has been adopted in some parts of Germany and neighboring countries, as in Carintha and Dognaska in the Banat. The improved apparatus consist of four connected reverberatory furnaces. DESCRIPTION OF DILLGER'S FURNACE. Fig. 4, represents partly the section and partly the elevation of these furnaces; and fig. 4* the plan of four of them together: 2 IS a, h, c, d, are the fire rooms of these furnaces, with their ash rooms: grates, or pierced vaults and doors. o-} h, are the charging doors of the chambers of these reverberatories, upon the floors of which are disposed a great number of baked long pots or tubes, about five feet long and six inches wide, closed at top, open at bottom. i, are side openings, by which the flame that passes into the chamber through k, the openings which vents itself into the hollow space be¬ tween the furnaces, and from thence into the I, chimney which serves for the whole set. m, are earthen pipes, open at both ends, and shaped like the capital of a column; the pipes are hung quite close together, in a grating of iron bars that form the real floor of the cham¬ ber; but as the square heads of these overlap the bars and meet together, they form the floor that is actually exposed to the heat. A groove in the edge of these pipes receive the open end of the p, long pots, and the prepared ore is prevented from falling out by some large pieces of charcoal which are stuck in the mouth of the long pots. r, are sheets of rolled iron, placed below the floors of the chambers to receive the drops of zinc that distil down from the short pipes. , s, are sheets of rolled iron, hung before the vault under the floor of the chamber, to hinder a draught of air on the zinc as it drops from the pipes, as that draught would cause the zinc to take fire. t, is the chimney of the whole stack of four furnaces. Each of these furnaces are, according to the plan, made for 160 pots, in 10 rows of 16 pots each, but only 38 of them charged with ore, are put into the furnace along with a sufficient number of unbaked empty pots to supply the place of those that break in the operation, which is usually about 28 or 30. The 64 pots of the first four rows next the fire room, are charged with a mixture of 14 cubic feet, or 1820 pounds of stamped and roasted calamine, 36 cubic feet, or 504 pounds of 19 bruised charcoal passed through a sieve whose meshes are only k of an inch wide; 36 pounds of common salt and 4 cubic feet or 280 pounds of water containing 3 pounds of potash in so¬ lution. Only 20 pots are placed in the two next rows, the space of 12 pots being left empty. These pots are charged with a mixture of four cubic feet or 520 pounds of stamped and roasted calamine, 16 cubic feet or 224 pounds of small pieces of charcoal, passed through a sieve whose meshes are \ inch wide, 16 pounds common salt, and one cubic foot or 62.5 pounds of water holding f pound of potash in solution. So that each of the pots hold 771 cubic inches or about 20 or 21 pounds of the mixture; the above quantity is the charge for two of these furnaces, which are usually heated at once, while the other pair are cooling. The furnaces are heated with beech billets, and the firing which lasts from 30 to 36 hours, consumes.about 72 cubic yards of wood. The 2340 pounds of roasted calamine in the above charge, produces about 800 pounds of raw zinc which is re¬ ceived on the sheets of iron, and being afterwards melted to be cast into ingots, yields about 700 pounds of pure zinc, and about 150 pounds of oxide, which is mixed with the calamine in the next operation. In some places, as in Poland and Silesia, stone coal is used; in that case some slight alterations are made in the construc¬ tion of the furnaces. In Silesia the pots are two feet wide. The breaking of these pipes and the great quantity of wood which it requires, reduces the profits very much, and may make this mode objectionable. Hollander's Tagebuch eincr metallur* gische technologische rcise, etc. DESCRIPTION OF THE LIEGE FURNACE. At Liege, calamine is distilled for zinc in another manner. The calamine is obtained from Altenberg, near Aix-la-chapelle. Earthen pipes are placed horizontally across the furnace, and open at both ends. The calcined calamine is ground to pow¬ der and mixed with from | to § of its bulk of coke broken up 20 to the size of a hazelnut. At Aix-la-chapefle, where a similar furnace Is in operation, charcoal is used. Fig. 5 represents a front view of the furnace at Liege, fig. 6? a vertical section through the midst of the furnace. Its height from the floor to the chimney is 9 feet. The height of the chim¬ ney is from 18 to 20 feet, ash hole; b, grate; c, fire place; d, floor of the furnace; c, Laboratory where the pipes are placed; f, arch which covers the laboratory; /, second arch which terminates the furnace; g, chimney; h, fire wall which is connected to the wall of the building. The floor of the furnace, the fire place and ash-hole are un¬ der the floor of the laboratory, so that the upper surface of the first is at the same level with that of the last. The heat rises from the fire place through i, 10 flues, two in a row; between these 5 pair of fines are placed the lower k, pipes which rest immediately upon the floor; the second and third row of pipes lie parallel above the lower, being a few inches the one from the other; in the sixth row are only two- pipes, so that there are in each operation 22 pipes. They are supported in the front and behind upon fire bricks^ which form in front with the side walls a kind of I, framework supporting the pipes. The pipes are 3 feet in length and from 4 to 5 inches diameter in the clear, and 5-4 of an inch thick. They are made of a mixture of fire clay and burned clay, and turned on a horizon¬ tal potter's wheel and shaped in a mould; they hold 40 pounds of mixture. The heat which passes through the flues i into the 1 aboratory, circulates around the pipes, and escaping through the m, openings in the two arches, reaches the chimney. To im¬ prove the draught there is an 21 n, aperture in the front of the furnace between the two arches, through which air can be introduced. The two small o, sidewalls of the furnace project one foot in front of the frame work I probably in order to have the p, 10 hooks on both sides, and the g, 5 iron bolts horizontally above one another, upon which rest the r, iron adapters. These adapters are of cast iron, conical, U foot long, their diameter is H inch at one extremity and 1 inch at the other. After the pipes are filled they are so attach¬ ed that they incline more or less backwards in order to prevent the fluid zinc from running away; the intermediate space is filled with loam. A small blue flame is perceptible at the mouth of the adap¬ ters during the operation of the furnace. The fluid metal is every two hours scraped out in a ladle; the operation is finished in about 12 hours, the pipes are then emptied, and filled with fresh materials, and the operation recommenced. Each opera¬ tion produces 100 pounds zinc, which is melted in cast iron pot^ and cast in proper forms, by which it loses about 10 per cent. In Silesia, Poland, Cracow, Galicia and Switzerland, the zinc distillation is generally practised in muffle furnaces. Several of these furnaces have lately been erected in the dominion of Beuthen in Silesia- There existed in 18.36;32 of these furnaces in Silesia, 28 at Beuthen and 4 atPless. The muffles are composed of a mixture of fire clay and pounded fragments of old muffles. The adapters or receivers, which arc not exposed to a great heat, are generally made of a mixture of common potter's clay and ground fragments of pots—two parts of the former and one part of the latter. DESCRIPTION OF THE SILESIAN FURNACE. Fig. 7 to 10 represents a double Silesian furnace;1 each for 10 muffles half of which have their mouths towards the one, and the other half towards the other side of the furnace; the two rows touch each other in the interior of the furnace. Fig. 22 7 exhibits at the left a ground plan in the direction of the dot¬ ted line a, b, c, d, in fig. 9; the right side, represents a super¬ ficial view, the arch and the half of the muffles being remov¬ ed. Fig. 8 represents a longitudinal view of the muffles, one half of which is furnished with iron doors and the other is without them. Fig. 9 shows a vertical section of a single fur¬ nace in the direction of the dotted line A. B. in fig. 7. Fig. 10, a transversal section of a single furnace and an outside view of half a furnace. a, a, a, three cast iron bars above the grate, which serve to introduce air and through which the ashes fall; they are fasten¬ ed in the masonry. by by by by four iron plates, enclosing the bars a, a, a. c, the fire hole closed with iron plates; it has an iron floor, and terminates towards the grate in d, a cast iron box. e, a cavity (called drophole) with an iron floor to receive the drops of metal. fy iron plate having on its outer edge an elevation, or simply turned up, to prevent the loss of zinc. ,g, the superior cover is, on both sides, a single iron plate, and forms at the same time the floor for the receivers. These plates are as long as the furnace, and one foot wide, and cov¬ er thus only the anterior part of the drop hole e. In order to close these cavities entirely hy complimentary plates are used which fit exactly in the place of the receiver and reach back to iy the apertures by which the communication between the receiver and the drop hole is established. Each plate g, in order to prevent their warping by heat, is fastened b\r k, three cast iron anchors in the form of a z. I, the walls of the fire place (the seat or the lower part of the furnace) are lined with the best fire bricks. The communication between the fire and the heating room is through the m, flue or channel. 23 The superior edge of the heating room is some inches high¬ er than the floor of the place for the receivers, so as to give a slight inclination to the hearth from the middle towards the sides of the furnace. The space between the seat (the lower part of the furnace) and the walls of the furnace are filled up with rubbish or sand. n, lateral flues or draught holes to heat the lateral muffles, o, horizontal entrance to clean the flues n, which are closed when the furnace is in operation. p, pillars from 3 to 5 inches across, made of a single piece of clay, the front part of which is externally covered with q, a small iron plate, which is fastened in the floor plate g. These pillars are not only the support of the arch of the small receivers arch, but for the cover of the furnace itself, which must be low, so that its highest part is not more elevated than 3 feet above the floor of the furnace. This arch is constructed with a mixture i part clay and I sand, having after its drying a thickness of 8 to 9 inches, r, six apertures in the roof of the furnace. s, hasps for the doors. t, doors. ,u, longitudinal anchor. v, cross anchor. w, standing anchor. x, muffles—they are placed in the open space between the pillars p upon the floor of the heating room, the open end is turned towards the front. The intermediate space between the muffles and the pillars, is, as soon as they are placed, fill¬ ed up with loam and fragments of pots. The mouth of the muffles is closed up with a well fitting plug of clay which is represented in fig. 11, (it is a section) cut out at 1 and at 2— the latter enters into the mouth of the muffles. z, receiver. The receiver is represented under fig. 12, and fig. 13, composed of, 3 the tube, 4 the head, 5 the neck, 6 the aperture in the head, through which the materials are introduc¬ ed into the muffles by means of Fig. 14 a shovel, and is closed during the operation. 24 DESCRIPTION OF THE FURNACE TO MAKE THE MUFFLES. Fig. 15 and 16 represents this furnace. The floor is cal¬ culated for five muffles; one long and four short ones. The grate is 10 inches lower than the floor of the furnace. a, the floor of the furnace. b, the fire bridge,—very high in order to diminish the current of the flame upon the floor, and to prevent it from touching the muffles. c, aperture through which the muffles are introduced and taken out. It is closed up with loose bricks during the oper¬ ation, so that the smoke can pass through the intermediate spa¬ ces and the flame may be seen. d, apertures through which the muffles are put in regular order. e, e, transversal arch to give strength to the feeble brick arch. f, fillings of sand below the floor. During the two first days the fire is placed under the grate. The heat is then gradually increased to a red heat which is kept up during two days. It takes from 8 to 10 days to burn the muffles completely. DESCRIPTION OF THE FURNACE TQ MELT THE COL¬ LECTED ZINC. Fig. 17 represents a front view of the furnace. Fig. 18 represents a transversal section. Fig. 19 represents a horizontal section. a, fire door. b, grate. c, fire bridge. d, flues. e, chimney. fififi earthen smelt pots. As soon as the new muffles, red hot from the furnace, fig. 15 and 16 are placed in the zinc furnace, they are without being fill- 25 ed, exposed to an extreme heat, they are then filled through the lower apertures in the receiving room with 66 pounds of roast¬ ed calamine mixed with about 20 pounds of cinders (small pie¬ ces of coke that have fallen through the grate) and a few pounds of oxide of zinc and scoria of previous smeltings of zinc; the receivers in the superior section are fitted, the lower receivers and all crevices and openings closed with clay, by which precaution the receivers become hot. Hardly 1 of an hour after the doors of the furnace have been closed, commences the distillation, (if the furnace is not new) and when in full progress lasts 6 or 8 hours longer. The metal rises in vapor into the receivers, where it condenses in drops which fall through the lower tube into the drop hole. When in contact with the air, part of the zinc can not be prevented from taking fire, so that some white oxide of zinc is collected in the neck and in the receiver itself^ and flakes of this oxide are seen to fly about through the place. It is generally calculated that from 2 to 4 per cent, of zinc is burned during the operation. The opera¬ tion is finished in about 24 hours; a second charge is intro¬ duced through the aperture in the head of the receiver, with¬ out removing the residue of the prior operation. After the second operation is finished the residue is taken out by the lower aperture in the muffle, the receiver is taken off, and when necessary, replaced by a new one, and the operation re- continued. The scorious residue in the muffle is composed of silex, alumina, iron and manganese oxides and zinc oxide, with lime and magnesia. The crude or drop zinc as it is called, (because it is compos¬ ed of a mass of connected drops) in order to change it into mercantile zinc, or to roll it in sheet zinc, is melted in earthen pots, which hold 10 centners, and are made of fire clay like the muffles. The heat during the melting of the zinc must not be raised too high, it is therefore necessary always to add some new zinc when it is melted to keep the heat uni¬ form. The melted zinc is then cast in moulds of cast iron in the form of plates one inch thick. If it is required to prepare sheet zinc, it is necessary that the zinc should be melted by the 26 lowest degree of heat, and the moulds in which the metal is cast, heated. Iron pots were formerly used to melt the zinc, but it was found that zinc acted too much upon iron, and that during the liquid state of the zinc a combination was formed of iron and zinc which rendered the iron pot soon useless, and the zinc becoming adulterated by iron was rendered brittle. EXTRACTION OF ZINC FROM BLENDE. In England the pounded blende (sulphuret of zinc) is roast¬ ed in a verberatory under constant stirring. A quadruple quantity of stone coal is used for this operation and the loss of ore is 20 per cent. The roasting lasts from 10 to 12 hours. In the smelting of zinc, one half of roasted blende and one half roasted calamine and one part, in bulk, of coal are used. The yield is generally, 30 per cent of zinc. In Switzerland, the blende is twice roasted, then worked up with one fourth of its bulk, of slacked lime and formed into bricks, 1000 of which are put in a reverberatory furnace, which is constructed somewhat like a potter's oven. The heating takes place with wood, for a cubic yard of these bricks one and a half cubic yards of wood are used. In the second roasting four reverberatory furnaces are used, which are con¬ nected with the four corners of the large reduction furnace (the same as described for Muffles, see page 21,) when its su¬ perabundant heat is yet advantageously used for the latter. In each furnace are introduced at once about seven quintal of roasted ore, carefully stirred, and from time to time some coals are added. The second roasting is finished in 24 hours, the loss during this operation amounts to 20 per cent. The roast¬ ed matter contains 28 oxide of zinc, 22,10 sulphate of zinc, 1 sulphuret of zinc and 47£ sulphate carbonate and caustic lime. The furnace in which the oxide of zinc is reduced is com¬ posed of two connected double furnaces like those used in Silesia (see page 21,) 12 quintal of roasted blende, as much as two furnaces can roast in a day, is reduced in 24 hours. Each muffle is filled with 25 pounds which are finished in 12 hours. After 16 operations the muffles are removed; they last on an 27 average one month. The yield from 300 pounds roasted blende by a distillation in 12 muffles is from 130 to 140 pounds impure zinc, or 43 to 46 per cent. The residue contains 5 4-10 of zinc. For such distillation 25 cubic yards of charcoal are used. De Villeneuve uber die zinc gewinnung aus der Blende, page 103. The zinc of commerce is generally in plates of about one inch in thickness, and often in the state of sheet zinc, which is mostly prepared in Germany. For the latter purpose, the zinc, whether it is first melted or yet in its crude state, (as it is not the quality of the zinc, but the mode of melting it which is now under consideration) is in the form of plates heated in a reverberatory furnace some what similar to those used in making sheet iron, but in which only a gentle heat is produced; the workmen find out in an empiric manner whether the zinc is properly heated, namely by spitting upon it, when the spittle moves over the surface in a gobular form and in this manner evaporates, the zinc is sufficiently heated; or he finds it out by slapping it with the flat of his hand. The rollers are also heat¬ ed to the above temperature, which temperature is generally kept up when thick plates are to be rolled. It takes 12 hours to roll from 12 to 14 quintal of sheets 6 by 2 feet in size, 10 or 11 of which weigh 100 pounds; and 24 to 25 quintal of sheets 3 by 2 feet, 14 or 15 of which weigh 100 pounds. After the rolling the sheets are once more annealed. In Belgium the an¬ nealing is performed in a solution of salt in water, which is heated to the required temperature. Chloride of lime, which in many chemical operations is produced and rejected, may answer this purpose. Zinc may be drawn out to pretty thin wire, for which never¬ theless a very malleable kind of metal must be selected. It is not necessary to enumerate the different properties of zinc, as they are generally known. One nevertheless should be mentioned, viz: that when sheet zinc is exposed to the action of air, it becomes covered with a very thin film of oxide, which prevents the metal below it from being further corroded, and thus makes zinc very fit to cover baths etc. with. Nevertheless some persons are opposed to the use of it, as they believe it is 28 soon destroyed by water and air—this however is a mistake. We know that the Hermitage in our vicinity is covered with zinc, which I believe is yet sound—I have kept sheet zinc for more than 30 years, often exposed, not only to the action of the air, but also occasionally to the action of acid vapors, and I find these plates of zinc yet sound, being as observed above merely coated with a thin pellicle of oxide, which a mere straping with a knife removes, and restores the bright metallic lustre. But the most important consideration is that zinc is readily sold at $6 per hundred, and that as yet no zinc has been extracted from its ore in the United States. I wish not, however, to be understood as recommending zinc for the covering of roofs. It has been already stated in this report that zinc is volatile at a red heat, and that when heated sufficiently, it takes fire and burns with a bright flame, throw¬ ing out in every direction flakes of burning oxide, consequently when a house covered with zinc, is once on fire, the zinc is apt to increase the combustion and the flying about of the zinc oxide makes it apparently dangerous to approach the fire. DESCRIPTION OP PROCESSES TO PREPARE BRASS. I will now proceed to notice one of the most important uses to which zinc is applied and in which the zinc existing in this state could all be employed—I allude to Brass. This impor¬ tant alloy is a mixture of copper and zinc in various porpor- tions, so intimately united as to form a homogeneous malleable yellow metal, applicable to a vast variety of purposes, and ca¬ pable of being wrought with the greatest facility. It is not easy to obtain a perfect union of zinc and copper by mere fusion in open vessels; for at a heat less than is required to melt the copper, the zinc readily takes fire and much of it burns off before it has time to combine with the copper, so that the proportion of zinc is constantly lessening by volatilization. Even after both metals are fused, the zinc continues to burn off in uncovered vessels, and at last scarcely any thing but cop¬ per is left. In order therefore to combine copper most inti¬ mately with zinc, and yet to preserve its malleability, the inge- 29 nious process of cementation has been resorted to in the manu¬ facture of brass. This is performed by heating in a covered pot alternate layers of copper in small pieces, with zinc ore and charcoal, and continuing the fire till the copper is throughly impregnated with zinc. Brass is manufactured in many countries from the ores of zinc. In the United States it is always made from the metal¬ lic zinc and copper. Pure or Rosette copper is broken up into small pieces, or as is practised in England, the fused metal is poured into a large ladle, pierced in the bottom with holes, and supported over a cistern of water. The water may be either hot or cold. When warm the copper assumes a round form, and is called beanshot. The Calamine, as mentioned before, is roasted and ground. In England some roasted blende is generally added. A great variety obtains in the respective proportions of the ingredients. According to Macquer in Goslar, 30 parts of copper 40 to 45 of Cadmia, (the oxide of zinc deposited in the chimnies of the furnaces as already mentioned*) and twice the volume of charcoal are used. In Paris and in many of the French manufactories, 35 of copper, 35 of old brass, 40 of cal¬ amine, and 20 to 25 of charcoal are employed; in Sweden, 30 of copper, 20 to 30 of old brass, and 46 of calamine with suf¬ ficient charcoal; or 40 of copper, 30 of old brass and 60 of cal¬ amine; in England 40 of copper and 60 of calamine. The product of brass varies also, but in no place is the yield so great qs in some of the English works, where 40 pounds of copper become in the process 60 pounds of brass. The prepared calamine being mixed with about a third or a fourth part of charcoal, is then ready for the brass furnace. * Several iron ores in East Tennessee particularly those occurring near Nolachucky river at the furnace of the late Mr. Embree, contain zinc which during the operation of the smelting of the ore is expelled by the heat and incrusts the upper part of the fumacei This incrustation is the c&dwiid al¬ luded to above. I have seen it at that furnace from U to 2 inches thick. This cadmia contains about 80 per cent of metallic zinc. The zinc may be extracted by any of the above mentioned modes, or it may he used imme¬ diately for the manufactore of Brass. It is now rejected. 30 The brass furnace has the form of the frustum of a hollow cone, or a cone with the apex cut off horizontally. At the bot¬ tom of the furnace is a circular grate or perforated iron plate, coated with clay and horse-dung, to defend it from the action of the tire., The crucibles or pots stand upon the circular plate, forming a circular row with one in the middle. The fuel, which is in England stone coal, is thrown round the crucibles, being let down through the upper opening or smaller end of the cone: over this opening is a perforated cover made of fire¬ bricks and clay, and kept together -with bars of iron, so as to fit closely. This cover serves to regulate the heat in the fol¬ lowing manner: the draught of air is formed through an under¬ ground vault to the ash-hole, thence through the grate and round the crucibles, and through the smaller upper opening into the area, where the workmen stand, which is covered by a large dome and a chimney to convey the smoke into the outer air. When the draught is the strongest, and a heat is required of the greatest intensity, the cover is entirely removed, and the flame then draws through the upper opening of the furnace to a considerable height into the outer brick dome; when the heat is to be lessened the cover is put on, which intercepts more or less of the draught from the furnace, as more or fewer of the holes of the cover are left unstopped. The crucibles are charged with the mixed calamine and char¬ coal, together with copper clippings and refuse bits of various kinds, and sometimes brass clippings also, most of which are previously melted and run into a small sunk cistern of wrater through a kind of colander as mentioned above. Powdered charcoal is put over all, and the crucibles are then covered and luted up with a mixture of clay or loam and horse-dung. The time required for heating the crucibles and completing the process, varies considerably in different works, being de¬ termined by custom, by quantity of materials, the size of the crucibles, and especially the nature of the calamine, in gene¬ ral firm ten to twenty-four hours are required. At Holywell in Flintshire, about twenty-four hours are taken. During the process, and especially towards the latter end, 31 part of the reduced zino which escapes absorption by the cop¬ per, finds its way in vapour through the luting of the crucible- lids, and burns around them with the beautiful blue flame and dense white smoke peculiar to this metal. The heat required for brass-making is somewhat less than what is necessary to melt large masses of copper, brass being the more fusible of the two, and the vapour of zinc being able, it would seem, to penetrate copper as soon as it is softened by a full red heat. When the brass is judged to be complete, and the saturation of the copper with zinc as high as possible, the heat is increased to melt the whole down into one clean mass at the bottom; the crucibles are then taken out and the metal poured into moulds. At Holywell, out of the six crucibles used to one furnace, the quantity of brass obtained is about as much as would fill one of them. This makes in subsequent manu¬ facture a single large plate, which is manufactured in the same way as copper plate. Or, more accurately, from forty pounds of copper and sixty pounds of calamine, about sixty pounds of brass are obtained, besides the loss of a good deal of zinc by the unavoidable escape of much of it in the form of vapour through the pores of the lute or the crucible-covers. The above is the usual process of brass-making in England as stated by A. & C. R. Aikin—and is essentially the same wherever this alloy is manufactured from the calamine, but with some variation as to the choice of ingredients and proportions. In Goslar in the Hartz, for instance, where brass is made in large quantities, the zinc is furnished not by native calamine but by the cadmia (sublimed oxide of zinc. See page 29.)— Which is collected for this purpose in a particular part of the chimnies of the furnaces in which the lead ores and blende are roastpd. At Stolberg, near Aix-la-Chapelle, where the brass is manu¬ factured, the furnaces are cylindrical, and each contains eight crucibles arranged in two tiers of four each. These crucibles are fifteen inches high, twelve inches deep, and eight or nine inches wide. The proportions of ingredients are 40 pounds of copper, 65 pounds of calamine, and double its volume of char- 32 coal. After the fire has been kept up for twelve hours, the cru¬ cibles are uncovered, and a workman takes off* with an iron trowel all the scum and charcoal which swim upon the liquid metal, and which is called arkest. When examined with a magnifying glass, this is found to consist of calamine and cop¬ per particles cohering together, but not completely united. The brass resulting from the first process is coarse, brittle, and un¬ equal in texture, and requires a second fusion before it is fit for use. For this purpose the same crucibles are again employed and are filled, first with three handfulls of the mixture of cala¬ mine and charcoal, over which are put two or three pounds of impure brass, broken in pieces, then more calamine and char¬ coal, with a lump of the arkest, and over all, calamine and charcoal powder. The crucible is then strongly heated for two hours, after which the brass is fit to be cast into plates, which is done in the following manner: A mould is formed of two blocks of granite, five feet long, three and a half feet broad, and eight inches thick. They are placed one above the other, the upper one only being moveable, and furnished with a tackle and pullies for that purpose, and before casting, the surface is smeared with cow-dung. To give the plate the re¬ quisite thickness, hoops of iron of different dimensions are adapted to the under stone so as to confine a determinate quan¬ tity of melted metal. The stones are then gently inclined and the melted brass let in between them. These plates are after¬ wards laminated. Some of them are cut into strips by strong shears, for the farther purpose of being drawn into wire and otherwise manufactured in various ways. A single process, where the fire is kept up long enough and the materials are good, is certainly sufficient to make good mal¬ leable brass, but it is probable that the excellence and beauty of the article are improved by making it undergo a second cemen¬ tation with fresh calamine and charcoal. Very fine bras's, it is said, may be made by mixing together the oxides of copper and zinc, and reducing them with a car¬ bonaceous flux. This idea is an ingenious one, and from the intimate mixture of the two metals, which it promises, it de- S3 serves to be further pursued. M. Sage, former assayer of the mint at Paris, gave the following experiment for this purpose: Mix together 50 grains of the oxide of copper which remains after the distillation of verdigris with 100 grains of lapis cala- minaris (calamine,) 400 grains of black flux and 30 grains of charcoal powder; melt the mixture in a' crucible till the blue flame is seen no longer round the lid of the crucible, and when- cold, a fine button of brass is found beneath the scoria, weigh¬ ing a sixth more than the copper alone, obtainable from its ox¬ ide in the same way, but without the calamine. This brass has a very fine color like gold. I mention this fact, in order that advantage may be taken of two natural products of the western country. The copper ore which occurs in Missouri State, is now transported to Baltimore to be smelted. This copper ore is mostly composed of red oxide of copper, (I know this to be a fact, as I was engaged last win¬ ter in analysing several varieties of the ore,) and it may be more profitably reduced and melted here, where fuel is abun¬ dant, than in Baltimore;—the transportation from Missouri here would be much less than to Baltimore, and the expense of pre¬ paring it for the formation of brass, (as it could be employed in its oxidised state,) would not be so great as that of making it into saleable copper. In that case, the brass could be made here at a less price than in any other part of the United States. I have been thus minute in my details respecting the mode of preparing brass from calamine without speaking of the man¬ ner in which it is generally made in this country, that is by combining the metallic zinc with copper. This mode has cer¬ tainly some advantages over the one in which calamine is used; the materials being in a smaller bulk than that of calamine, and the operation not so complicated. If the materials were to be purchased, this mode would certainly be preferable; but I am speaking here of the calamine that we have in Tennes¬ see, which, when properly prepared, may be used immediately as well 5ir brass as for metallic zinc. The operation, whether for brass or for zinc, is almost the same, so that we avoid here¬ by the whole of the complicated process of reducing the cala- 34 mine to zinc, which certainly more than balances all the ad¬ vantages which I here enumerated in preference of metallic zinc. ANALYSES OF ORES FROM CLAIBORNE COUNTY. The lead ores which contain zinc and which occur in Clai¬ borne county, 15 or 20 miles from Tazewell, near Powell's river, and in fact, which are visible at the bottom of this river, have also engaged my attention. I could not well determine its ex¬ tent and direction when I visited this locality, Powell's river be¬ ing too high and inundating the places where the ore made its appearance at the surface of the ground. It has since, if I am not mistaken, been cleared from its incumbent matter, and, as I understand, the prospects of an abundance of ore are very promising. I have since received samples of these ores which I have analysed, and I found some of them remarkably rich in zinc. A specimen taken from the bed of Powell's river, given to me by the Hon. Senator Thornburg, was composed of: Lead, 75,00 Zinc, 11,00 Sulphur, 12,50 A trace of silver loss, 1,50 100,00 Another from a ridge near Powell's river. Lead, Zinc, Sulphur, Iron oxide, Carbonic acid and silex, 40,00 29,00 15,00 6,00 10,00 100,00 A third from the sanj j vicinity. Lead, Zinc, Carbonic acid,1 Sulphur, 53,00 15,00 6,00 11,00 35 Iron oxide and earthy matter, 13,00 Loss, 2,00 100,00 I have, since the above analyses were made, received some •ore frpm Mr. Nelson. This gentleman has published, in one of our public papers, the analyses that were made by me, and if I am not mistaken, has said something of the extent and of other circumstances relating to these mines. I obtained some¬ what similar results from Mr. Nelson's ores as from the Hon. Mr. Thornburg's—they are: Zinc, 32,00 Lead, 21,00 Sulphur,* 13,00 Iron, 6,00 Earthy matter and loss, 28,00 100,00 Another specimen gave me. Lead, 71,00 Zinc, 10,00 Sulphur, 11,00 Iron, 2,00 Silver, a trace, Earthy matter and loss, 6,00 100,00 From these analyses it appears that the ore of Powell's river, is an irregular mixture of blende (sulphuret of zinc) and galena, (sulphuret of lead,) in which sometimes the one and sometimes the other prevails. When pure galena, it will be composed of 86| of lead and 13| of sulphur, and when pure blende, it will contain 66 of zinc and 34 sulphur. The iron, and other matter, riientioned as earthy matter, silex and carbonic acid are accidental, and have not been considered in the analyses. Whenever the zinc can be employed advantageously, then 36 these lead ores will be very profitably used, by the operatioii for the extraction of lead the zinc will be changed into cadmia, spoken of at page 29. I have also been engaged in the examination of other min¬ eral productions of our State, and I have analysed several min¬ eral waters. The analysis of those which possessed any ben¬ eficial qualities have been published in our periodicals by the proprietors of those Springs. I have analysed several new¬ ly discovered minerals, some of which proved of no value, oth¬ ers on the contrary I found of great importance for our State. Amongst the latter I have to mention the deposit of iron ore discovered by Col. Dickson, which is situated near the left bank of the Tennessee river, in Perry county, and judging from the little that has been cleared from its superincumbent soil, promises to be of great extent, and being situated in the finest wooded country, will augment our mineral resources very much. This ore is a mixture of brown hematite and compact brown iron stone—the hydroxide of iron of mineralogists— with hardly any intermixture of heterogeneous matter, and proved by analysis to be composed of: Peroxide of iron, 83 Oxide of manganese, 1 Water, 14 Earthy matter, 2 100 Consequently it will yield about 58 per 100 of malleable or har iron. It is the purest and richest of any of the iron ores of Ten¬ nessee that I have analysed, and being so favorably situated, it will add very much to the mineral resources of our State. Some specimens of iron ore were handed to me by Mr. Mad¬ ison Napier takes from a deposit in Hickman county, which according to Mr. N. is very extensive. This ore also is the hydroxide of iron as the former and is composed of: 37 Peroxide of iron, G3 Oxide of managese 2 Water and volatile matter, 15 Earthy Matter, 20 100 So that it will yield about 43 per 100 of malleable or bhr iron. I received for analysis two Varieties of iron ore from Mr. William Williams from Knoxville, East Tennessee. The one belongs to what mineralogists call specular iron ore and forms a sub-species or variety knowers under the name of red scaly iron ore, vulgarly called dye ore. It is of a reddish brown col¬ or—of a glistening semi-metallic lustre, and composed of fri¬ able scaly particles more or less cohering together. It stains the fingers and is unctuous to the touch. The scaly structure mentioned above is not displayed through the whole mass—it presents at several places a len¬ ticular form being composed of: Peroxide of iron, 65 Earthy matter, 35 100 The earthy matter is principally silex. So that this ore will yield about 43 per 100 of malleable or bar iron. I have examined this ore at the place where it occurs, and found it pretty, homogeneous, almost free of any intermixture of other matter, and very abundant on the eastern declivity of the Cumberland mountains. I believe the vein can be traced for about 60 miles, at least I found it with a few interruptions from near the Alabama line to the Cumberland gap. The second specimeh handed to me by Mr. W. Williams is an ore which is similar to the two already described, the hydrox¬ ide of iron, and coincides with the generality of the iron ore of Middle Tennessee. Mr. Williams' specimen was a mixture of 38 Compact brown iron stone, and hematite with a small quantity of ochre, brown iroh. From the analysis to which I have subjected it, it appears to be composed of: Peroxide of iron, 79:5 Oxide of manganese, 1:0 Water, 15:0 Earthy matter, 4:5 100:0 Consequently containing about 55 per 100 of malleable or bar iron. Mr. Williams also handed to me a specimen of coal from a bank near the Tennesstee river and in the vicinity of the above described iron ores. This coal has a striking resemblance to that of Messrs. Gillenwater and Kimbrow on the Cumberland Mountains, which I understand is highly appreciated for the steamboats, and at New Orleans for the gas works. From analysis it appears to be composed of: Volatile and bituminous matter, 17 Carbon Coke, 76 White ashes, 7 100 The Coke which it produces is very porous and light, which perhaps would not make it fit for the iron furnaces, but it must be observed that I operated on a small quantity, under hardly any pressure, it is therefore possible that when the cokeing is performed on a large scale, it will be more compact and heavy, this must be ascertained by experiments on a large scale. I doubt whether any coal of the Cumberland mountain has ev¬ er been subjected to the cokeing process on an extensive scale. I also haVe made analysis of several varieties of the lime¬ stone of our State and found some of them equal to hydraulic limestone. A stratum which comes to light near Parady's hill, Davidson county, is composed of: 39 On the same vertical line with silex, Carbonate of Lime, containing a small quantity of Magnesia, 73:5 Silex, 17:5 Alumina, 9:0 100:0 All of which is very respectfully submitted. G. TROOST, Geologist of the State, Fig. 3. 12 3 4 9 10 Scale ol Fie. 3. I I I I 20 feet. '1' 1 1 11 r"7""i 1—$3^^^ *SS;"«&.3Ss«3i.S3U :v»,;3 sarSit-X'W : ... , ,v. . . .,3;^^^-^:,^..; §0 fisfeOK ■ no -O -Fa fo von a' !BiSl&&r PLATE I. Fig. 4. Fig. 4#, 6^ / J. 1! .© ■ ® k \. & > AS O" k A «t5 *•> k' $ "N \ k k ,vs k ^ * N \ k k yg *sy c.y | *s.« A ^s, oSN <5* k k | k A. 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